Hydraulically actuated pump



June 4, 1968 D. Rosr-:NBERG 3,386,388

HYDRAUL I CALLY ACTUATED PUMP Filed June 22, 1966 United States Patent O3,386,388 HYDRAULICALLY ACTUATED PUMP David Rosenberg, 12 Francis Court,Glen Cove, N.Y. 11542 Filed June 22, 1966, Ser. No. 559,547 14 Claims.(Cl. 103--152) ABSTRACT F THE DISCLOSURE A hydraulically actuateddiaphragm pump is provided having a check valve in a line from thehydraulic source to the chamber adjacent the diaphragm. A secondhydraulic line connects the pump valve with the hydraulic source. Thecheck valve creates a differential pressure between the chamber and thesecond hydraulic line on a stroke of the pump to maintain the sequenceof movement between the diaphragm and the pump valve.

This invention relates to fluid devices, and more particularly to uiddisplacement pumps of the type adapted to iluid actuation.

Metering and proportioning pumps for the movement of chemical solutionsand the like are known, in which a pumping impulse is provided to thepumping mechanism in the form of a fluid impulse, such as an oscillatingilow of hydraulic uid in an actuating line connected to the pumpingmechanism. This is a convenient arrangement, because the volume and thefrequency of the pump strokes can be very accurately regulated byadjustment of the source of the iluid impulses.

The pumping mechanism itself is frequently a diaphragm pump actuated bythe pumping impulses, and provided with inlet and outlet valves for thecontrol of the iiow of the pumped liquid.

Since the pumped liquid frequently is a chemical additive, which mayoften be in the form of a slurry, and frequently is in the form of adissolved or diluted material, it is common for the pumping mechanism tobe required to handle a liquid suspension of undissolved or insolubleparticles, especially when it has pumped down toward the end of a batchor container-full of the additive rnaterial. Such particles are usuallylimited in size to those smaller than the mesh dimensions of anappropriate inlet screen, so that blockage of the pump by a single largeparticle seldom occurs. Many of the suspended solids which it is desiredto pump, however, display the inconvenient property of breaking out ofsuspension near regions of turbulence, coagulating and building up 0nnearby parts of the pump;

When this occurs on the pump valves, and especially on the inlet valve,it causes it to leak, thus destroying the metering accuracy of the pump,and it is not unusual for it to cause the inlet valve to refuse to closeat all during some strokes of the pump, thus destroying itseifectiveness. Similar deposits can also build up on the outlet valve.

Even in cases where such extreme consequences do not occur, many ofthese suspensions, such as those of talc, chalk or fullers earth, ordiatomaceous earth, are highly abrasive, and result in a rapid wear anddestruction of the pump valves and seats due to the erosive effect ofthe suspension when it flows through a partly closed valve at highvelocity.

Another diiculty experienced in the construction of metering pumps isthat if accuracy of measurement is desired, the pump valves must bedesigned to be as small as feasible. This is because, since they arenecessarily provided with a resilient seal, the precise closed positionof the valve is always somewhat in doubt because of the compressibilityof the seal, which allows the valve to as- Patented .lune 4, 1968 ICBsume differ-ent positions according to the pressure exerted upon it.Minimizing the size of the valve thus reduces but cannot eliminate thechanges in pumping chamber volume arising from this cause, andaccentuates all of the aforementioned diiculties due to suspendedmaterial in the pumped iluid, both because of the diiculty ofconstructing such a small part with precision, and because of increasedow velocity and consequent erosion which such small size requires.

Slurry pumps are known which overcome many of these ditiiculties byproviding pressure-actuated valves which are of relatively largedimensions, and are driven between open and closed positions accordingto the fluid pressure impulse applied in a separate hydraulic system,which is also in fluid pressure connection with the hydraulic cham-berof the pump to actuate the pump. Such pumps are shown in U.S.application Ser. No. 396,794, led on Sept. 4, 1964, now U.S. Patent No.3,256,825.

Pressure-actuated valves can be formed of a size suiiicient to ensureaccurate and reliable operation in pumping slurries, and to reduce theflow through the valve to the point where `excessive deposition ofslurried particles does not occur. Moreover, it is possible to form thevalves and seats of a hard material which is highly resistant toabrasion and which can be 'formed with sufficiently sharp edges to cutthrough any deposits which may form, thereby having a self-cleaningaction.

An even greater degree of accuracy has been obtained by having one ofthe valves hydraulically actuated and biased (such as by a spring)against the actuating hydraulic pressure to keep the valves open orclosed, as desired. Generally, the pump inlet valves are biased open,and the outlet valves are biased closed. Biasing is especially importantwhen pumping highly concentrated, a-brasive slurries. However, theaccuracy of the pump can be seriously impaired if the other valve isoperated directly by the pumped slurry. Particles more readily aredeposited in the valve, preventing the valve from fully closing, whenthe operation of the valve is dependent upon the pressure exertedagainst the upstream face of the valve by the pu-mped slurry.

When both valves are operated by a separate hydraulic system, theproblems of clogging and sticking of the valves are substantiallyeliminated, even when pumping highly concentrated abrasive slurries.However, other problems are encountered when Iboth the inlet and theoutlet valves, as well as the pumping member, are biased andhydraulically activated. All of the bias members have to be veryprecisely calibrated so that the valves and the pump are actuated by thesame hydraulic pressure at the same time, i.e. the inlet valve open orclose, the outlet valve close or open and the pumping member expand orcontract, respectively, at the same hydraulic pressure in the hydraulicpressure system at the same time. The problems of maintaining such exactresponse in commercial operations are overwhelming. Furthermore, thebias means, such as springs, normally do not all wear at the same rate,and inaccuracies soon develop during operation, requiring constantadjustment of the pump settings.

It has now been found, however, that hydraulicallyactuated, biased inletand outlet valves can be used together in a hydraulically-actuated pumpwith only approximately calibrated bias means, wherein the exact forceexerted -by each of the bias means is not critical to the accuracy ofthe pump. Furthermore, according to this invention, the valves andpumping member can -be actuated in any desired order.

The bias members are preferably calibrated so that on the compressionstroke of the pump a relatively low hydraulic pressure actuates theinlet valve to close, the

same or a relatively higher hydraulic pressure actuates the outlet valveto open and a still higher hydraulic pressure, the highest of the three,actuates the pumping member. According to this invention, means are alsoprovided such that during the intake stroke of the pump the outlet valvecloses first, at the relatively highest hydraulic pressure, the inletvalve opens simultaneously or subsequently at the same or at arelatively lower hydraulic pressure, and the pumping member is actuatedlast at the relatively lowest hydraulic pressure. ri`he term effectivehydraulic pressure as used herein refers to the pressure differentialacross the pressure-responsive member in question, such as a diaphragmor piston eX- posed on one side to hydraulic system pressure and on theother side to pump system pressure.

The invention accordingly provides a pump for supplying fluid through aline compising, in combination, a pump chamber; a pressure chamber; anda diaphragm therebetween normally biased towards a rst position; a fiuidconnection through the pump chamber for flow of fluid to and from thechamber; a fiuid pressure-responsive valve having open and closedpositions and disposed across the line of fiuid flow through the pumpchamber for controlling the iiow of iiuid therein, said valve ybeingnormally biased towards one of the open and closed positions; ahydraulic system comprising a source of hydraulic pressure; a firsthydraulic fiuid connection to the pressure chamber for fiow of pressurefluid to the pressure chamber for movement of the diaphragm away fromthe first position to pump iiuid through the pump chamber and the `fluidconnection therethrough; a second hydraulic fluid connectioncommunicating the fiuid pressure-responsive valve with one of thepressure and pump chambers of the pump for movement of the valve awayfrom its first position to the other of its positions in response totiuid pressure in the chamber; the valve and the diaphragm being movedin a predetermined sequence by predetermined hydraulic pressuresdeveloped by the hydraulic source in the second hydraulic fiuidconnection and in the pressure chamber, respectively; and regulatingmeans in said first hydraulic fiuid connection producing on alternatestrokes of the pump a pressure difference between the pressure chamberand the second hydraulic fiuid connection greater than the differencebetween the effective bias strength acting on the valve and theeffective bias strength acting on the diaphragm, thereby maintaining thesequence of movement of the valve and the diaphragm upon each successivestroke of the pump.

The term stroke is intended to describe a complete movement of thediaphragm in a single direction between its extreme positions, i.e. theintake stroke and the exhaust stroke.

Preferably, the regulating means comprises check valve means in thefirst hydraulic fluid connection, bias means operatively connected tosaid check valve means in a manner permitting the valve to open to flowin one direction at a substantially zero pressure drop across the valveand permitting the valve to open to fiow in the other direction only ata predetermined pressure drop across the valve, the effective strengthof the bias means acting upon the check valve being greater than thedifference between the effective bias strength on the diaphragm and theeffective bias strength on the Valve.

Thus, on the pressure stroke, upon increase in hydraulic fluid pressurein the hydraulic system, the increased pressure is communicated to thepressure-responsive valve which is actuated to its second position, i.e.the inlet valve to a closed position or the outlet valve to an openposition, and then actuates the diaphragm. lf the valve is an inletvalve, the lbias means acts to hold it open, and the valve is driven toa closed position upon increase in pressure in the pressure chamber. lfthe valve is an outlet valve, the bias means acts to hold it closed, andit is driven to an open position, upon increase in pressure in thepressure chamber. On the intake stroke, when the hydraulic pressure isrelaxed, the valve is first moved back to its first position, i.e. theoutlet valve is first closed or the inlet valve first opened, and thenthe diaphragm moves to draw in uid to the pump chamber.

Preferably, the inlet and outlet valves are hydraulically actuated andbiased. The bias means acting on the diaphragm as well as those actingon both valves can be so set that they are actuated at the same pressurein the hydraulic system provided by the pulse means. In the preferredembodiment, where both valves are hydraulically actuated and biased,both valves are preferably actuated before the diaphragm on bothstrokes, and the inlet valve is preferably actuated at a lower hydraulicpressure than the outlet valve, for greatest accuracy of operation. Asused hereafter, the effective strength of the bias means and theeffective bias strength refers to the effective hydraulic pressurerequired to overcome the `bias means.

The regulating biased check valve means can include a singledouble-seating valve or a pair of check valves, one 4being free `to opento fiow in one direction, i.e., unbiased, and the other being biasedagainst opening to flow in the other direction, located in parallelhydrau'ic fiuid connections between the hydraulic pressure source andthe pressure chamber of the pump.

The direction in which the biased check valves operate depends upon therelative effective strength exerted by each of the bias means acting onthe diaphragm and on the valve. If the bias member on the diaphragm hasthe greatest effective strength, the check valve of zero pressure isopened when a positive pulse of hydraulic pressure is applied on thepressure stroke of .the pump, i.e. when hydraulic fluid flows into thepressure cham-ber of the pump. The biased valve lis opened during thereverse ow, when the hydraulic pulse is relaxed and fluid flows out ofthe hydraulic chamber. The biased check valve operates only after thedifference between the hydraulic pressure in the rest of the hydraulicsystem and in the pressure chamber, or the pressure drop across thecheck valve, is greater than the effective strength of the check valvebias means. If the bias means on the valve is stronger than that on thediaphragm, the check valves act in the reverse direction.

The bias means on the check valve need only be greater than thedifference between the effective strengths ot' the valve bias means andthe pump bias means. The inlet -or the outlet valve is thereby closed oropened, respectively, prior to the movement of the diaphragm on thepressure stroke and is similarly actuated to be opened or closedrespectively prior to the movement of the diaphragm on the intakestroke. This arrangement is suitable when one or both of the inlet andoutlet Valves are biased and actuated hydraulically.

Preferably, when both the inlet and the outlet valves and the diaphragmare biased and hydraulically actuated, the inlet valve bias means hasthe lower effective force. However, if desired, these valve bias meanscan have substantially equal effective strengths.

The pump Valves as used in this invention generally include a valve bodyand `a valve seat disposed across the line of fiow through the pumpchamber. The valve body is mounted for to and fro movement between openand closed positions away from and in contact with the valve seat. Biasmeans are connected to the valve body to retain it in either an open orclosed position. Fluid pressure-responsive means are attached to thevalve body for moving it against the action of `the bias means and thefluid pressure responsive means is in fiuid connection with one of thechambers of the pump, usually the pressure chamber.

Preferably, the source of hydraulic pressure is a pulsing means such asa piston pump having means to supply on each pressure stroke of thepiston a known volume of hydraulic fluid to the hydraulic chamber ,todstend the diaphragm. The preferred pump is an adjustable recipro.

eating piston pump of the type shown in U.S. Patent No. 2,869,467,discussed above. In that pump, on each suction stroke of the piston, thecylinder is vented to a reservoir of oil which in .turn is vented to theatmosphere. Any air or other gas which may collect in the hydraulicchamber of the diaphragm pump is thereby swept out of the cylinder intothe reservoir and then to the atmosphere. The fact that the pumpingcylinder is immersed in a reservoir of oil prevents any additional airfrom entering the hydraulic chamber during the venting. Pulsing systemsother than reciprocating piston pumps are also suitable for use in theinvention, such ras a rotary piston pump. The hydraulic system of thesepumps include the hydraulic pressure chamber `of the pump, any conduitsconnecting that chamber to the pulsing means and valves, and usually,the pulsing means itself.

The pumps of the invention can include a plurality of diaphragms, in themanner, for example, shown in U.S. Patent No. 3,100,451. The pumpingchamber or alternatively, the pulsing or hydraulic chamber, can, forexample, be in the form of a cylinder, closed at each end by animpermeable flexible diaphragm, with the bias means always in thepulsing or hydraulic chamber or chambers. In the case of a doublediaphragm pumping chamber, the tension bias means is placed outside thediaphragms, and the hydraulic liquid is supplied to the hydraulic-chambers outside the diaphragms. In the case of a double diaphragmhydraulic chamber, the tension bias means is placed between thediaphragms and the hydraulic liquid is supplied to the chambertherebetween for flexing action of the diaphragms in the pumpingchambers. In such a structure, two different liquids could be pumped,and one diaphragm could be stopped (an adjustable stop can be used) sothat the other receives a pressure effect of a proportion of the volumeof hydraulic fluid supplied, the total amount of this fluid in turnbeing adjusted by the effective stroke of the pisto-n. If but one liquidis to be pumped, the Valves can be manifolded so that la single outletcould be used.

The bias means is of the tension or compression type depending upon theposition of the hydraulic chamber and the direction of the bias forcerequired. Any form of 4bias means can be used. Coil springs, disksprings, also known as Belleville springs or washers, and resilientbushings or plugs are typical, and various embodiments thereof are shownin the drawings. These can be made of any suitable material, usuallymetal, such as stainless steel, carbon steel, nickel, brass and bronze,or plastic, such as rubber, synthetic rubber, polyamides, polypropylene,polyvinyl butyral, or metal coated with any inert plastic material.

The diaphragrns employed in the proportioning pumps of the invention canbe -made of any sheet material which is suiciently ilexible andresilient to be flexed under uid pressure, and which can be returned tonormal nonflexed position when the fluid pressure is relieved, aided, inaccordance with the invention, by bias means. Desirably, the diaphragmcan withstand many .millions of such exures without damage.

For additional strength, the sheet diaphragm can be provided with abacking material or plate which will prevent damage due tooverpressuring, and can also serve to control .the amount of flexureunder a given fluid pressure.

In addition, to increase flexibility, a diaphragm can be formed as acomposite or multiple ply structure. Two or more exible sheets, of thesame or different material, can be laminated or clamped together to formthe diaphragm. If the sheets are laminated, they can be joined togetherwith an adhesive material, by welding or any other suitable means. Theuse of a laminated or clamped structure of very thin sheets increasesthe strength of a diaphragm of a given resiliency, thereby allowing fora greater ran-ge for exing on each stroke of the diaphragm. The laminateis preferably designed so that the outer plies are strong in tension andthe center plies strong in compression. The

laminate can also be formed of materials with directional strength byalternating directions of axes in each ply. In the case of pluraldiaphragms, the diaphragms can all be laminated, or only one can belaminated, as desired. The laminated diaphragm can be designed -to havethe same or a different resiliency than the single ply diaphragm.

The configuration of the diaphragms can be selected according to thepumping requirements. For instance, the diaphragm can be of uniformthickness throughout its area. It can also be designed to be thicker atthe center than at the periphery, so as to increase its resistance toflexing. The shape of the diaphragm is quite immaterial and the`diaphragm can be circular, elliptical, polygonal, rectangular, squareor indeed any shape, according to the design of the hydraulic or pulsingand pumping chambers. Thus, for example, the diaphragms can be made ofsheet metal, such as stainless steel, Monel metal, aluminum, copper,carbon steel, brass, tin, nickel and zinc, or of a resilient plasticsheet material such as ru-bber, synthetic rubber, neoprene, Viton A,urea-formaldehyde, melamineformaldehyde, phenol-formaldehyde,polymethylmethacrylate, nylon, polystyrene, polytetrafluoroethylene,polyt-riuorochloroethylene, polypropylene, polyethylene, polyvinylchloride, polyvinylidene chloride and polycarbonate resins, and epoxyresins; and fiber-reinforced laminates of any of these materials, erg.glass fiber, cotton fiber, linen fiber and the synthetic fibers such asnylon.

The back-up plates or other materials used, if desired, forreinforcement can be made of the same or different materials. Thus, forinstance, a stainless steel diaphragm can -be supported by a stainlesssteel plate or by a plastic plate, and a rubber diaphragm can bereinforced by a stainless steel plate or by a plate made ofpolytetrauoroethylene or nylon. These are merely illustrative examples,and other combinations will be apparent to those skilled in the art fromthe above description.

The pulsing or hydraulic fluid can be selected as desired, according tothe bias means employed, and 'will be inert to the bias means, thediaphragm and hydraulic chamber walls. Any hydraulic uid can be used.The hydraulic fluid can, for example, be a lubricating oil or othernon-corrosive petroleum liquid, a silicone oil, or a polyalkylene glycolether.

The pressure-responsive means acting on the valve can take any ofseveral forms. A diaphragm is especially aclvantageous, and ispreferred. The diaphragm can be of flexible material, such as metal, forinstance, stainless steel, iron, steel, aluminum, tin, nickel-chromiumalloy, or copper, or plastic, such as polyamide, polytetrauoroethylene,polycarbonate, polystyrene, polyethylene, or polypropylene. It can beresilient, such as rubber, or synthetic rubber, or a sheet spring, suchas a Belleville spring disc or washer, affixed to a piston-type orpoppet valve. Reinforcing support can be provided a ydiaphragm ofstructurally weak material.

A bellows also can be used, really a form of folded diaphragm, and madeof any of the above materials.

In some uses, a piston means operated in a cylinder is particularlydesirable. A piston can be combined with a diaphragm to increase thesurface area open to pressure actuation in one direction and thuspermits high hydraulic fluid pressure for actuating the pump diaphragmWithout exceeding permissible valve seating pressure and/ or valvediaphragm bursting pressures. Such a valve is shown in application Ser.No. 396,794, led Sept. 4, 1964, now.

U.S. Patent No. 3,256,825,

The bias means for the valve include a tension or compression spring, orappropriate design and resiliency including any of the types set forthabove for the diaphragm bias means. The inherent resiliency of the valveactuating member, -such as a stainless steel diaphragm can be employedto like purpose. A Belleville washer can be used to retain the valve ineither the open or the closed positions, to ensure return of the valveto one of such positions in response to change in fluid pressure. Amagnetic pressure responsive means can be used, attracted to acorresponding magnetic means at the position at which the valve is to beretained. One or both of such magnetic means can be magnets.

The drawings show several preferred embodiments of the invention.

FIGURE l is a sectional View of a tluid displacement pump havingpressure-responsive valves constructed in accordance -with the presentinvention, and utilizing diaphragms as the pressure-responsive means.

FIGURE 2 is a partial sectional view of an alternative form of hydrauliciluid connection bet-Ween the pressure chamber and the pulsing means forFIGURE 1.

Referring to the drawings, the diaphragm pump shown in FIGURES l and 2includes a pump section 1, a hydraulic section casing 2, a valve sectioncasing 3 and a pulsing means section 4. The sections 1, 2, 3 and 4 areheld together by bolts passing through flanges not shown. Dened withinthe pumping section 1 are pump chamber 5 and inlet and outlet conduits 7and 9 to the pump chamber. Also defined within the pump section is aportion of a hydraulic line 10. Defined within the hydraulic section 2is the hydraulic pressure chamber 12, hydraulic line 10, in alignmentwith the portion of hydraulic line in the pump section 1, and parallelhydraulic lines 14 and 15 connecting the hydraulic line 10 to thehydraulic pressure chamber 12.

Diaphragm defines one wall of the pumping chamber 5 and one wall of thehydraulic chamber 12. The flexible diaphragm 20 is clamped between thehydraulic casing 2 and the pump casing 1. Bolt 24 passes through acentral opening in the diaphragm 20 and is threaded into a hanged nut 22on the pumping chamber side of the diaphragm. To prevent leakage throughthe diaphragm, a sealing nut 25 is threaded on -bolt 24 on the hydraulicchamber side of the diaphragm, and nuts 22 and 25 clamp on to thediaphragm 20, to form a leakproof seal. At the far end of bolt 24 is thebolt head 27.

The compression coil spring 29, for biasing the diaphragm, is heldbetween a perforated back-up plate 30, also clamped at its peripherybetween the pump casing 1 and the hydraulic casing 2, and the spider 32,which is tted between bolt head 27 and sealing nut 25. Two perforations31 and 33 in the back-up plate 30 are aligned with hydraulic lines 14and 15 respectively. Thus, whenever the diaphragm 20 is flexed outwardlyinto the pumping chamber 5, such movement is against the action of thespring 29, which tends to pull the diaphragm back in the direction ofthe hydraulic chamber. As a result, when the hydraulic Huid pressuretending to force the diaphragm outwardly is released, the spring 29pulls the diaphragm 20 back to the normal nonexed position shown in FIG-URE l.

The parallel hydraulic lines 14 and 15 are provided with check valves 35and 37, respectively. The rst check valve 35 comprises a valve seat 40,Valve ball 41 and compression spring 42 acting as the bias member. Therst check valve 35 prevents any flow through line 14, when positivepressure is applied by the pulsing means through line 10, into thehydraulic chamber 12. In the reverse direction, check valve 35 willpermit flow from the hydraulic chamber 12 only after the pressure dropacross the valve is sucient to overcome the force of compression spring42.

The second check valve 37 comprises valve seat 44, ball valve 45 andstop members 46. The second check valve 37 permits flow into thehydraulic chamber 12 when positive pressure is applied by the pulsingmeans through the hydraulic line 10. The check valve 37 prevents anyflow in the reverse direction from the hydraulic chamber when thepressure pulse is released.

The valve section 3 of the pump comprises a top casing Sil, a centralcasing 5l and a lower casing 52. The top, middle and bottom casings 50,5l and 52, respectively, are held together by bolts not shown and anyleakage at the joints is prevented by gaskets 59, which can be formed aspart of the diaphragm. The middle casing 5l, can be formed in two parts,if desired, to permit changing of the individual valves.

The top casing St) defines an extension of the pump outlet conduit 9,the Valve chamber 55 and valve outlet conduit 57. Valve seat 5S isinserted into the top casing 5t) and defines the upper surface of thevalve chamber 5S. The valve diaphragm 61 is clamped between the top andcentral casings 50 and 51. The central casing 51 denes the valvehydraulic chambers 64 and hydraulic fluid lines 68, 69 connecting thehydraulic chambers 64 to the main hydraulic fluid line 1) in the pumpsection 1. Bolt 72 passes through a central opening in the diaphragm 61and flanged nut 70 in the hydraulic valve chamber 64 is threaded on tothe end of bolt 72. To prevent leakage through the diaphragm 61, asealing nut 74 is threaded on to bolt 72 on the hydraulic side of thediaphragm 6l and nuts 74 and 73 clamp on to the diaphragm 61 to form aleakproof seal. Perforated plate 75 rests against an outer surface ofcasing 51 and serves as a stop for the diaphragm 61. The bias spring 63is mounted between the spider member 76 and the perforated plate 75 tobias the diaphragm in the same manner as by the bias spring 29 for thepump diaphragm 28'.

Bolt Sti is threaded into the top face of the flanged nut 73 and extendsupwardly through the valve seat 58. Ball valve 81 is secured to the topof bolt 8G at a position such that it will be held tightly against thevalve seat 58 by the force exerted by bias spring 63.

The lower casing 52 of the valve section defines the inlet valve chamber90, the extension of inlet line 7 connecting to the valve chamber 90.Inlet valve seat 92 is placed into a slot in the bottom valve casing 52.

Diaphragm 62 is clamped between the bottom and central valve casings 51and 52. The construction and biasing of the diaphragm 62 in the inletvalve with bias spring 89 is identical to that in the outlet valvedescribed above.

Bolt 95 is threaded into the outer face of ilanged nut 73 and extendstowards the valve seat. Ball valve 97 is threaded onto the end of bolt95 in a position such that when the diaphragm 62 is extended into theinlet valve chamber by a hydraulic pulse in the hydraulic chamber 64,the ball valve 97 will be held securely against the Valve seat 92. Asshown the hydraulic valve chambers 64 are separate. However, in analternative embodiment, the two chambers can be joined as one withoutany loss in etfectiveness.

The hydraulic line 10 can be attached to any hydraulic pulsing meanswhich will provide periodic hydraulic pulses of a delinite volume.Preferably, however, the pulsing means is a piston-operated hydraulicpump such as that described in U.S. Patent No. 2,869,467, particularlyFIGURE 8 thereof. The pulsing means will preferably have adjusting meanswhich will set the volume of the hydraulic pulse transmitted to thehydraulic chamber of the pump and the valves so as to regulate thevolume of material swept by the diaphragm 20 of the pump.

In the particular embodiment shown in FIGURE l, the spring 29 of thepump has the greatest effective strength, equal to approximately 3()p.s.i. pressure drop across the diaphragm, for example. The spring 63 ofthe outlet valve has the next highest effective strength, equal to, forexample, about 25 p.s.i. pressure drop across the diaphragm 6l, and thespring 89 of the inlet valve has the lowest effective strength, equal toabout 20 p.s.i. pressure drop across the diaphragm 62. The effectivestrength of spring 42 in check valve 35' is greater than the differencebetween the effective strengths of the spring 29 and spring 89,approximately 12 p.s.i., in this example. The exact strength of eachbias means is not critical, as long as the relationship between themremains the same.

ln operation, the hydraulic pulsing means is adjusted to periodicallysupply a predetermined volume of hydraulic fluid, in this case oil,through the line 10 and line 15 to the hydraulic chamber 12 and to theoutlet and inlet valve hydraulic chambers 64 through lines 68 and 69respectively.

When a positive hydraulic pulse is exerted by the pulsing means, fluidflows through line 10 and through line 15 into the hydraulic chamber andthrough lines 68 into the valve hydraulic chambers 64. As the pressurebegins to increase in each of the hydraulic chambers, the first biasmeans is overcome, the inlet valve bias means 89, and the inlet valvediaphragm 62 is pushed outwardly into the inlet valve chamber 90 forcingball valve 97 to seat firmly against valve seat 92. This closes theinlet to the pump and prevents fluid from passing into or out of thepump chamber through line 7. As the pressure increases in the hydraulicsystem of the pump, the next bias means is overcome, spring 63 of theoutlet valve, and diaphragm 51 is forced outwardly into the outlet valvechamber 55 unseating ball valve 81 from valve seat 58 and opening theoutlet from the pump so as to permit fluid flow from the pump chamber 5through the outlet line 9. Finally, the pump bias means 29 is overcomeand the diaphragm 53 flexed outwardly into the pumping chamber 5 andfluid is pushed out.

On the negative stroke of the hydraulic pulsing means, when thehydraulic pressure is being reduced, fluid flows outwardly from thehydraulic chambers through line 10, leaving the valve hydraulic chambers64 and pump hydraulic chamber 12 through lines 68, 69 and 14,respectively. Fluid cannot flow outwardly from the hydraulic chamber 12of the pump until the pressure difference across valve 35 is greaterthan the effective strength of spring 42, i.e in this case about 12p.s.i. Accordingly, the pressure in the pump hydraulic chamber 12 is notreduced until the valve 35 is open. As the pressure is decreased in thehydraulic system, the first valve to be actuated is the outlet valve 81which seats against valve seat 5S as soon as the hydraulic pressuredrops below the effective strength of its bias member 63. As thepressure continues t-o drop, the hydraulic pressure against the inletvalve diaphragm 63 is relaxed until it is less than the effectivestrength of spring 89. The bias spring then moves the valve 97 away fromseat 92, opening the inlet valve. When the pressure drop across valve 35is greater than 12 p.s.i., the valve opens permitting fluid to leave thehydraulic chamber 12. When the hydraulic pressure acting againstdiaphragm 20 is less than the effective strength of the bias means 29,the diaphragm 20 moves back to its first position, drawing in pump fluidthrough inlet line 7. The perforated plate 30 acts as a stop to preventfurther movement of the diaphragm beyond the limiting position, ifnecessary.

As the diaphragm 20 moves back from its flex position, upon reduction ofpressure in the hydraulic chamber 12, fluid enters the pumping chamber 5until the fluid in the chamber equals the volume of the chamber.

By adjustment of the volume of fluid delivered to line and of thepulsing period of the hydraulic pulsing means, it will be apparent thatany desired volume of fluid from the pumping chamber can be assured.

The inlet and outlet valves of FIGURE 1 can be readily replaced by othertypes of hydraulically actuated valves. One of the valves can beactuated by the fluid flow through the pump. Examples of various typesof valves are set forth in U.S. application Ser. No. 396,794, filedSept. 4, 1964 now U.S. Patent No. 3,256,825 issued on June 2l, 1966.

FIGURE 2 shows the portion of the pump of FIGURE l outlined by thebroken line wherein the two parallel hydraulic conduits 14 and 15 arereplaced by the single conduit 16 containing check valve 100. Checkvalve 100 comprises ball valve 102 which can move between stops 103 andthe sliding annular orifice member 104. The sliding annular orificemember permits flow through its central opening but will not permit flowaround its outer edges when it is pushed up against valve seat by thecompression spring 107. The remaining portion of the pump can beidentical to that shown for FIGURE 1.

In operation, when the hydraulic pulse pressure is increasing, the ball102 is pushed forward against stop 103 permitting flow to pass throughline 16. On the reverse stroke of the hydraulic pulse when the hydraulicfluid is flowing out of the pump chamber the ball is pushed againstsliding orifice plate 104 plugging the orifice and preventing flowtherethrough. As the pressure drop across the valve increases to a pointsufficient to overcome the effective strength of the compression spring107, the annular plate 104 slides backwardly along the line 16 away fromvalve seat 105 permitting flow to pass through line 16. Accordingly, thesame result is obtained with the single passage as was obtained by thepair of parallel conduits of FIGURE 1 with check valves 35 and 37.

When the present invention is utilized with diaphragm pumps having morethan one diaphragm, and more than one pressure chamber such as the pumpset forth in U.S. Patent No. 3,100,451, the check valve of thisinvention can be installed upstream of both hydraulic pressure chambers.In this case, one set of check valves will be lo'cated between bothhydraulic pressure chambers and the hydraulic pulsing means.Alternatively, two sets of check valves can be used, one in thehydraulic connection to each hydraulic pressure chamber.

Similarly, several different pumps can be operated by a single hydraulicsystem. Each pump can have a separate diaphragm and a separate hydraulicpressure chamber attached to the same source of hydraulic pressure, oralternatively, several different diaphragms, one for each of severaldifferent pumping chambers, can form the walls of the same pressurechamber. The regulating means in either of such pumps can be located inthe conduit immediately downstream of the pressure source, or wheredifferent pressure chambers are involved regulating means can beinstalled immediately upstearm of some or all of the pressure chambers.

Having regard to the foregoing disclosure, the following is claimed asthe inventive and patentable embodiments thereof.

1. A pump for supplying fluid through a line comprising, in combination,a pump chamber; a pressure chamber; and a diaphragm therebetweennormally biased towards a first position; a fluid connection through thepump chamber for flow of fluid to and from the chamber; a fluidpressure-responsive valve having open and closed positions and disposedacross the line of fluid flow through the pump chamber for controllingthe flow of fluid therein; said valve being normally biased towards oneof the open and closed positions; a first hydraulic fluid line forconnecting a source of hydraulic pressure and said pressure chamber forcommunication of source pressure to said pressure chamber for movementof said diaphragm away from said rst position to pump fluid through saidpump chamber and said fluid connection therethrough; valve meanspositioned in said first hydraulic fluid line such that flow of fluid toand from said pressure chamber proceeds via said valve means; a secondhydraulic fluid line bypassing said valve means for connecting saidsource of hydraulic pressure and said fluid pressure responsive valvefor communication of source pressure to said fluid pressure responsivevalve for source pressure responsive movement of said fluid pressurerepsonsive valve between its respective positions; the fluid pressureresponsive valve and the diaphragm being moved in a pre-determinedsequence by pre-determined hydraulic pressure developed by said sourcein said second hydraulic fluid line and in said pressure chamber,respectively; said valve means permitting free flow of fluid into saidpressure chamber but permitting flow of fluid out of said pressurechamber only upon a pre-determined pressure differential across saidvalve means, producing on alternate strokes of the pump a pressuredifference between the pressure chamber and assasss the second hydraulicfluid line greater than the difference between the effective biasstrength acting on the valve and the effective bias strength acting onthe diaphragm, thereby maintaining the sequence f movement of the valveand the diaphragm upon each successive stroke of the pump.

2. A diaphragm pump in accordance with claim 1 wherein the valve meanscomprises check valve means in the first hydraulic fluid line, biasmeans operatively connected to said check valve means in a mannerpermitting the valve to open to flow in one direction at a substantiallyzero pressure drop across the valve and permitting the valve to open toflow in the other direction only at a predetermined pressure drop acrossthe valve, the effective strength of the bias means acting upon thecheck valve being greater than the difference between the effective biasstrength on the diaphragm and the effective bias strength on the valve.

3. A pump in accordance with claim 1 wherein the fluid pressureresponsive valve is disposed across the fluid inlet to the pumpingchamber.

4. A pump in accordance with claim l wherein the fluid pressureresponsive valve is disposed across the fluid outlet from the pumpingchamber.

5. A pump in accordance with claim 4 wherein a second fluidpressure-responsive valve is disposed across the fluid inlet to the pumpchamber for controlling the flow of fluid thereto, the valve having openand closed positions and being normally biased towards one of the openand closed positions, this valve also being connected to said source ofhydraulic pressure for movement of said second fluid pressure responsivevalve in response to source pressure.

6. A pump in accordance with claim 5 wherein the effective bias strengthacting on the diaphragm is greater than the effective bias strengthacting on the outlet valve which is in turn greater than the effectivebias strength acting on the inlet valve and wherein the pressuredifference between the pressure chamber and the second hydraulic fluidline is greater than the difference between the effective bias strengthacting on the pump diaphragm and the effective bias strength acting onthe inlet valve.

7. A pump in accordance with claim 5 wherein the effective bias strengthacting on the diaphragm is greater than acting on either valve andwherein the pressure difference between the pressure chamber and thesecond hydraulic fluid line is greater than the difference between theeffective bias strength acting on the pump diaphragm and the effectivebias strength acting on the outlet valve.

S. A pump in accordance with claim l wherein the rst hydraulic fluidline comprises two parallel fluid conduits, the conduits each having acheck valve, one check valve preventing flow in a first direction, thesecond check valve preventing flow in the other direction, the firstconduit having a check valve unbiased to open at substantially zeropressure in one direction and the other conduit having a check valvebiased to prevent flow of fluid therethrough in the other directionuntil a predetermined pressure drop is produced across the check valve.

9. A pump in accordance with claim 1 wherein the first hydraulic fluidline comprises a single fluid conduit including a double-acting valveset to open in a first direction to fluid flow at substantially zeropressure drop and biased in the other direction, to prevent the valvefrom opening until a predetermined pressure drop is produced across thedouble-acting valve.

10. A pump in accordance with claim 1 wherein the pressure-responsivevalve includes a diaphragm.

i2 il. A pump in accordance with claim 1 wherein the pressure responsivevalve includes a bellows.

12. A pump in accordance with claim l wherein the pressure-responsivevalve and bias means are combined 5 and comprise a resilient Bellevillespring.

13. A pump in accordance with claim 1 wherein the pressure responsivevalve includes a piston reciprocatingly mounted in a cylinder.

14. A pump for suppling fluid through a line comprising, in combination,a pump chamber, a pressure chamber and a diaphragm therebetween; firstbias means operatively connected to the diaphragm and normally retainingthe diaphragm in a first position; a first fluid connection through thepump chamber for flow of a fluid to and from the chamber; an inlet Valveand valve seat and an outlet valve and valve seat disposed across theline of fluid flow through the pump chamber for controlling the flow offluid therethrough, the inlet and outlet valves being mounted for to andfro movement between open and closed positions, respectively, away fromand toward the valve seat; valve bias means operatively connected toeach of said valves and normally retaining said valves in a firstposition, the inlet valve in an open position and the outlet valve in aclosed position; fluid pressure-responsive means operatively connectedto each of the valves; and a hydraulic system comprising hydraulic pulsemeans; a first hydraulic fluid connection between the pulse means andthe pressure chamber for flow of pressure fluid to the pressure chamberfor movement of the diaphragm away from the first position to pump fluidthrough the pump chamber; a second hydraulic fluid connectioncommunieating the fluid pressure-responsive means with the pulse meansfor movement of the inlet and outlet Valves away from their firstposition to their other position in response to fluid pressure in thehydraulic system, the valves and the diaphragm being moved in apredetermined sequence by predetermined hydraulic pressure developed bythe pulse means in the second hydraulic fluid connection and in thepressure chamber, respectively; and regulating means in said firsthydraulic fluid connection for maintaining the order of actuation of thevalves and the diaphragm by hydraulic pressure during successive strokesof the pump comprising check valve means in the first hydraulic fluidconnection, bias means operatively connected to said check valve meansin a manner permitting the valve to open to flow in one direction at asubstantially zero pressure drop across the valve and permitting thevalve to open to flow in the other direction only at a predeterminedpressure drop across the valve, the effective strength 0f the bias meansacting upon the check valve being greater than the difference betweenthe effective bias strength on the diaphragm and the effective biasstrength on the valves.

References Cited ROBERT A. OLEARY, Examiner.

W. I. KRAUSS, Assistant Examiner.

